Illinois Creek

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale MZ
Quadrangle map, 1:63,360-scale B-1
Latitude 65.266
Longitude -153.1338
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Illinois Creek placer mine (Cobb, 1972, location 6) is in section 33, T. 2 S., R. 28 E., Kateel River Meridian. It is approximately 6.5 miles upstream from the mouth of Illinois Creek on the Yukon River, and 2.5 miles east of Switchback Mountain. The location is accurate within half a mile. Illinois Creek has several tributaries that have been placer mined, including Golden Creek (MZ018) , Linda Creek, and several tributaries with names that suggest mining including Gold Run Creek, Miner Creek, Nugget Creek, and Shovel Creek.

Geologic setting

Geologic description

The rocks in the vicinity of Illinois Creek and its tributaries are Precambrian or Paleozoic, greenschist-grade micaceous quartzite and quartz-chlorite-muscovite schist, and subordinate glaucophane-bearing schist, marble, and greenstone (Patton and others, 1977). The closest igneous body is the quartz monzonite and granite Melozitna pluton, whose southern border is about 8 miles north of Illinois Creek. Patton and others (1977) date the pluton as Early Cretaceous based on a K-Ar date of 111 +/- 3 Ma. The Kaltag fault, an east-northeast, high-angle structure, is approximately 7 miles south of Illinois Creek.
Good prospects were reported in 1911 on Illinois Creek, but prospecting was seriously hindered by thick, thawed gravel deposits (Eakin, 1912; Cobb, 1975). One hole was sunk to a depth of 133 feet without reaching bedrock, but several beds bearing fine gold were intersected (Eakin, 1913). In 1929, there was renewed interest in known occurrences of placer tin on Illinois Creek, its tributary Golden Creek (MZ018), and Moran Creek (MZ016). At different times there were reports that the placer concentrates contained considerable cassiterite as well as gold (Wimmler, 1929). A little drilling was done on Illinois Creek in 1929 but the work was soon suspended. An undetermined small amount of placer gold has been recovered on Illinois Creek, but no cassiterite (Chapman and others, 1963). From 1978 to 1982, placer mining took place on Illinois Creek at its junction with Golden Creek (MZ018) (Kardex file 047-010; unpublished record, Alaska Division of Mining, Land & Water). The stream gradient of Illinois Creek is about 75 feet per mile.
Geologic map unit (-153.136326727666, 65.2654575610863)
Mineral deposit model Placer Au (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration Good prospects were reported in 1911 on Illinois Creek, but prospecting was seriously hindered by thick, thawed gravel deposits (Eakin, 1912; Cobb, 1975). One hole was sunk to a depth of 133 feet without reaching bedrock, but several beds bearing fine gold were intersected (Eakin, 1913). In 1929, there was renewed interest in earlier-known occurrences of placer tin on Illinois Creek, its tributary Golden Creek (MZ018), and Moran Creek (MZ016). At different times there were reports that the placer concentrates contained considerable cassiterite as well as gold (Wimmler, 1929). A little drilling was done on Illinois Creek in 1929 but the work was soon suspended. From 1978 to 1982, placer mining took place on Illinois Creek at its junction with Golden Creek (MZ018) (Kardex file 047-010; unpublished record, Alaska Division of Mining, Land & Water).
Indication of production Yes; small
Production notes An undetermined small amount of placer gold was recovered on Illinois Creek from 1911 to 1982, but no cassiterite (Chapman and others, 1963).

Additional comments

This site is the Illinois Creek, U.S. BLM MILS location 0020470003 (Oddenino and others, 1995; Interagency Minerals Coordinating Group, 2004).

References

MRDS Number A015575

References

Interagency Minerals Coordinating Group, 2004, Alaska Mineral Locations Database [MAS (Minerals Availability System) and MILS (Mineral Industry Location System)], http://imcg.wr.usgs.gov/dem.html (select Melozitna quadrangle).
Reporters G.E. Graham, D.J. Szumigala (Alaska Division of Geological and Geophysical Surveys)
Last report date 1/18/2005